| Biography | |
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 Dr. Asad Ullah Department of Mathematical Sciences, Karakoram International University Gilgit, Pakistan |
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| Title: Realistic grain growth simulations in three-dimensional polycrystalline microstructures and evaluation of growth rate models | |
| Abstract: Monte carlo simulation is one of the important and widely used methods for polycrystalline grain growth simulations. Although, it has very close correspondence with the evolution of real structures, however, predicting the initial conditions of the microstructure for simulation is a challenge and still a little is known about it. Many researchers used the algorithms to create a virtual microstructure that appears similar to real microstructures, but often these virtual microstructures lack important microstructural details that significantly affect the results of the models. Therefore, a perfect representation of the initial state of microstructure is necessary to obtain realistic and unbiased results. In this research, An easy to implement and efficient methodology for simulations of grain growth in realistic three-dimensional (3D) polycrystalline microstructures is presented. The techniques of digital image processing and analysis are applied to incorporate real 3D reconstructed volume of the microstructure into simulations, which may be very helpful for a better representation of the initial state of microstructure to obtain realistic and unbiased results. Based on the simulation results of real microstructures (pure iron), the applicability of exact and average growth rate models is investigated. Digital image processing and segmentation techniques in conjunction with mathematical morphology models are used to reconstruct the 3D grains in real polycrystalline microstructure. Digital image analysis techniques are then applied to extract the grain morphologies from reconstructed microstructure. The extracted real grain morphology data is used as initial condition and incorporated the real reconstructed structure into simulations. The generally accepted Monte carlo Potts model simulation method is used to simulate grain growth in pure iron microstructure. Based on the simulation data of realistic microstructure, grain growth rate models are evaluated. By using the techniques of discrete and computational geometry, algorithms are developed to measure the geometrical and topological parameters like volume, surface area, face number, mean width and length of triple lines etc. of 3D grains in the microstructure. | |
